This disclosure relates to a display device with a touch detection function, and in particular, to a display device with a touch detection function detecting touch events based on a change of an electrostatic capacitance in response to an external proximity object, and an electronic unit including such a display device with a touch detection function.
In recent years, a display device capable of inputting information by mounting a contact detection device, which is a so-called touch panel, on a display device such as a liquid crystal display device, or integrating the touch panel and the display device, and displaying various button images and the like on the display device instead of typical mechanical buttons has attracted attention. The display device including such a touch panel does not require input devices such as a keyboard, a mouse, and a keypad, and therefore there is a tendency to expand the use of such a display device to portable information terminals such as mobile phones, in addition to computers.
In the touch detection method, some methods are included, and one of them is an electrostatic capacitance type. For example, in Japanese Unexamined Patent Application Publication No. 2009-244958 (JP-A-2009-244958), a display device in which a common electrode originally provided in the display device for display is also used as one electrode of a pair of touch sensor electrodes, and the other electrode (touch detection electrode) is arranged to intersect with the common electrode has been proposed. In addition, in Japanese Unexamined Patent Application Publication No. 2008-217784 (JP-A-2008-217784), a touch panel including a plurality of electrodes formed along X-axis direction and Y-axis direction has been proposed. Moreover, in U.S. Pat. No. 7,382,139, a sensor device including three electrodes with different widths depending on a position on one layer has been proposed. Further, in Japanese Unexamined Patent Application Publication No. 2010-86236 (JP-A-2010-86236), a touch panel which includes a plurality of electrodes formed along X-axis direction and Y-axis direction and an uneven region for preventing touch errors formed on an operation surface of the touch panel has been proposed. The touch panel is also configured to have a constant electrostatic capacitance even in a case where such an uneven region is provided.